Understanding COVID-19-associated coagulopathy: From PIC to SIC or DIC

Viral sepsis: diagnosis, clinical features, pathogenesis, and clinical considerations

Sepsis, characterized as life-threatening organ dysfunction resulting from dysregulated host responses to infection, remains a significant challenge in clinical practice. Despite advancements in understanding host-bacterial interactions, molecular responses, and therapeutic approaches, the mortality rate associated with sepsis has consistently ranged between 10 and 16%. This elevated mortality highlights critical gaps in our comprehension of sepsis etiology. Traditionally linked to bacterial and fungal pathogens, recent outbreaks of acute viral infections, including Middle East respiratory syndrome coronavirus (MERS-CoV), influenza virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), among other regional epidemics, have underscored the role of viral pathogenesis in sepsis, particularly when critically ill patients exhibit classic symptoms indicative of sepsis. However, many cases of viral-induced sepsis are frequently underdiagnosed because standard evaluations typically exclude viral panels. Moreover, these viruses not only activate conventional pattern recognition receptors (PRRs) and retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) but also initiate primary antiviral pathways such as cyclic guanosine monophosphate adenosine monophosphate (GMP-AMP) synthase (cGAS)-stimulator of interferon genes (STING) signaling and interferon response mechanisms. Such activations lead to cellular stress, metabolic disturbances, and extensive cell damage that exacerbate tissue injury while leading to a spectrum of clinical manifestations. This complexity poses substantial challenges for the clinical management of affected cases. In this review, we elucidate the definition and diagnosis criteria for viral sepsis while synthesizing current knowledge regarding its etiology, epidemiology, and pathophysiology, molecular mechanisms involved therein as well as their impact on immune-mediated organ damage. Additionally, we discuss clinical considerations related to both existing therapies and advanced treatment interventions, aiming to enhance the comprehensive understanding surrounding viral sepsis.

COVID-19 and Subsequent Development of Pancytopenia With Concurrent Disseminated Intravascular Coagulation

Complications resulting from coronavirus disease 2019 (COVID-19) sequelae have been well documented. These include blood conditions such as lymphopenia, thrombocytopenia, and hypercoagulability. Less common problems that may arise are disseminated intravascular coagulation (DIC), immune thrombocytopenic purpura (ITP), and pancytopenia. Furthermore, the majority of COVID-19 patients to develop pancytopenia have been immunosuppressed. We present a case of a previously immunocompetent patient who subsequently developed pancytopenia, DIC, as well as symptoms of ITP one month after being diagnosed with COVID-19.

Disseminated intravascular coagulation complicating mild or asymptomatic maternal COVID-19

BACKGROUND

Hypercoagulability frequently complicates moderate or severe COVID-19 and can result in venous thromboembolism, arterial thrombosis, or microvascular thrombosis. Disseminated intravascular coagulation, however, is uncommon.

OBJECTIVE

We sought to describe the clinical presentation and outcome in a series of pregnant patients with mild or asymptomatic COVID-19 who had disseminated intravascular coagulation.

STUDY DESIGN

This was a retrospective case series. Cases were solicited via e-mails targeted to obstetrical providers in the Mednax National Medical Group and a restricted maternal-fetal medicine Facebook page. Inclusion criteria were: hospital admission during pregnancy, positive test for SARS-CoV-2 within 2 weeks of admission, and maternal disseminated intravascular coagulation defined as ≥2 of the following: platelet count ≤100,000 per mm3, fibrinogen ≤200 mg/dL, and prothrombin time ≥3 seconds above the upper normal limit. Exclusion criteria were severe COVID-19 requiring ventilation within an hour of diagnosis of coagulopathy or use of anticoagulants at the time of diagnosis. Maternal and newborn records were abstracted and summarized with descriptive statistics.

RESULTS

Inclusion criteria were met in 19 cases from October 2020 through December 2021. Of these, 18 had not received any COVID-19 vaccine, and 1 had unknown vaccination status. Median gestational age on hospital admission was 30 weeks (interquartile range, 29-34 weeks). The main presenting symptom or sign was decreased fetal movement (56%) or nonreassuring fetal heart rate pattern (16%). COVID-19 was asymptomatic in 79% of cases. Two of the 3 defining coagulation abnormalities were found in 89% of cases and all 3 in the remaining 11%. Aspartate aminotransferase was elevated in all cases and ≥2 times the upper normal limit in 69%. Only 2 cases (11%) had signs of preeclampsia other than thrombocytopenia or transaminase elevation. Delivery was performed on the day of admission in 74% and on the next day in the remaining 26%, most often by cesarean delivery (68%) under general anesthesia (62%) because of nonreassuring fetal heart rate pattern (63%). Postpartum hemorrhage occurred in 47% of cases. Blood product transfusions were given in 95% of cases, including cryoprecipitate (89% of cases), fresh/frozen plasma (79%), platelets (68%), and red cells (63%). Placental histopathology was abnormal in 82%, with common findings being histiocytic intervillositis, perivillous fibrin deposition, and infarcts or necrosis. Among the 18 singleton pregnancies and 1 twin pregnancy, there were 13 live newborns (65%) and 7 stillbirths (35%). Among liveborn neonates, 5-minute Apgar score was ≤5 in 54%, and among cases with umbilical cord blood gases, pH ≤7.1 was found in 78% and base deficit ≥10 mEq/L in 75%. Positive COVID-19 tests were found in 62% of liveborn infants.

CONCLUSION

Clinicians should be alert to the possibility of disseminated intravascular coagulation when a COVID-19 patient complains of decreased fetal movement in the early third trimester. If time allows, we recommend evaluation of coagulation studies and ordering of blood products for massive transfusion protocols before cesarean delivery if fetal tracing is nonreassuring.

The potential role of ischaemia-reperfusion injury in chronic, relapsing diseases such as rheumatoid arthritis, Long COVID, and ME/CFS: evidence, mechanisms, and therapeutic implications

Ischaemia-reperfusion (I-R) injury, initiated via bursts of reactive oxygen species produced during the reoxygenation phase following hypoxia, is well known in a variety of acute circumstances. We argue here that I-R injury also underpins elements of the pathology of a variety of chronic, inflammatory diseases, including rheumatoid arthritis, ME/CFS and, our chief focus and most proximally, Long COVID. Ischaemia may be initiated via fibrin amyloid microclot blockage of capillaries, for instance as exercise is started; reperfusion is a necessary corollary when it finishes. We rehearse the mechanistic evidence for these occurrences here, in terms of their manifestation as oxidative stress, hyperinflammation, mast cell activation, the production of marker metabolites and related activities. Such microclot-based phenomena can explain both the breathlessness/fatigue and the post-exertional malaise that may be observed in these conditions, as well as many other observables. The recognition of these processes implies, mechanistically, that therapeutic benefit is potentially to be had from antioxidants, from anti-inflammatories, from iron chelators, and via suitable, safe fibrinolytics, and/or anti-clotting agents. We review the considerable existing evidence that is consistent with this, and with the biochemical mechanisms involved.

Pharmacotherapy consideration of thrombolytic medications in COVID-19-associated ARDS

BACKGROUND

In late 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which is responsible for coronavirus disease (COVID-19), was identified as the new pathogen to lead pneumonia in Wuhan, China, which has spread all over the world and developed into a pandemic. Despite the over 1 year of pandemic, due to the lack of an effective treatment plan, the morbidity and mortality of COVID-19 remains high. Efforts are underway to find the optimal management for this viral disease.

MAIN BODY

SARS-CoV-2 could simultaneously affect multiple organs with variable degrees of severity, from mild to critical disease. Overproduction of pro-inflammatory mediators, exacerbated cellular and humoral immune responses, and coagulopathy such as Pulmonary Intravascular Coagulopathy (PIC) contributes to cell injuries. Considering the pathophysiology of the disease and multiple microthrombi developments in COVID-19, thrombolytic medications seem to play a role in the management of the disease. Beyond the anticoagulation, the exact role of thrombolytic medications in the management of patients with COVID-19-associated acute respiratory distress syndrome (ARDS) is not explicit. This review focuses on current progress in underlying mechanisms of COVID-19-associated pulmonary intravascular coagulopathy, the historical use of thrombolytic drugs in the management of ARDS, and pharmacotherapy considerations of thrombolytic therapy, their possible benefits, and pitfalls in COVID-19-associated ARDS.

CONCLUSIONS

Inhaled or intravenous administration of thrombolytics appears to be a salvage therapy for severe ARDS associated with COVID-19 by prompt attenuation of lung injury. Considering the pathogenesis of COVID-19-related ARDS and mechanism of action of thrombolytic agents, thrombolytics appear attractive options in stable patients without contraindications.

Clinical applications of machine learning in the survival prediction and classification of sepsis: coagulation and heparin usage matter

BACKGROUND

Sepsis is a life-threatening syndrome eliciting highly heterogeneous host responses. Current prognostic evaluation methods used in clinical practice are characterized by an inadequate effectiveness in predicting sepsis mortality. Rapid identification of patients with high mortality risk is urgently needed. The phenotyping of patients will assistant invaluably in tailoring treatments.

METHODS

Machine learning and deep learning technology are used to characterize the patients' phenotype and determine the sepsis severity. The database used in this study is MIMIC-III and MIMIC-IV ('Medical information Mart for intensive care') which is a large, public, and freely available database. The K-means clustering is used to classify the sepsis phenotype. Convolutional neural network (CNN) was used to predict the 28-day survival rate based on 35 blood test variables of the sepsis patients, whereas a double coefficient quadratic multivariate fitting function (DCQMFF) is utilized to predict the 28-day survival rate with only 11 features of sepsis patients.

RESULTS

The patients were grouped into four clusters with a clear survival nomogram. The first cluster (C_1) was characterized by low white blood cell count, low neutrophil, and the highest lymphocyte proportion. C_2 obtained the lowest Sequential Organ Failure Assessment (SOFA) score and the highest survival rate. C_3 was characterized by significantly prolonged PTT, high SIC, and a higher proportion of patients using heparin than the patients in other clusters. The early mortality rate of patients in C_3 was high but with a better long-term survival rate than that in C_4. C_4 contained septic coagulation patients with the worst prognosis, characterized by slightly prolonged partial thromboplastin time (PTT), significantly prolonged prothrombin time (PT), and high septic coagulation disease score (SIC). The survival rate prediction accuracy of CNN and DCQMFF models reached 92% and 82%, respectively. The models were tested on an external dataset (MIMIC-IV) and achieved good performance. A DCQMFF-based application platform was established for fast prediction of the 28-day survival rate.

CONCLUSION

CNN and DCQMFF accurately predicted the sepsis patients' survival, while K-means successfully identified the phenotype groups. The distinct phenotypes associated with survival, and significant features correlated with mortality were identified. The findings suggest that sepsis patients with abnormal coagulation had poor outcomes, abnormal coagulation increase mortality during sepsis. The anticoagulation effects of appropriate heparin sodium treatment may improve extensive micro thrombosis-caused organ failure.

A central role for amyloid fibrin microclots in long COVID/PASC: origins and therapeutic implications

Post-acute sequelae of COVID (PASC), usually referred to as 'Long COVID' (a phenotype of COVID-19), is a relatively frequent consequence of SARS-CoV-2 infection, in which symptoms such as breathlessness, fatigue, 'brain fog', tissue damage, inflammation, and coagulopathies (dysfunctions of the blood coagulation system) persist long after the initial infection. It bears similarities to other post-viral syndromes, and to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Many regulatory health bodies still do not recognize this syndrome as a separate disease entity, and refer to it under the broad terminology of 'COVID', although its demographics are quite different from those of acute COVID-19. A few years ago, we discovered that fibrinogen in blood can clot into an anomalous 'amyloid' form of fibrin that (like other β-rich amyloids and prions) is relatively resistant to proteolysis (fibrinolysis). The result, as is strongly manifested in platelet-poor plasma (PPP) of individuals with Long COVID, is extensive fibrin amyloid microclots that can persist, can entrap other proteins, and that may lead to the production of various autoantibodies. These microclots are more-or-less easily measured in PPP with the stain thioflavin T and a simple fluorescence microscope. Although the symptoms of Long COVID are multifarious, we here argue that the ability of these fibrin amyloid microclots (fibrinaloids) to block up capillaries, and thus to limit the passage of red blood cells and hence O2 exchange, can actually underpin the majority of these symptoms. Consistent with this, in a preliminary report, it has been shown that suitable and closely monitored 'triple' anticoagulant therapy that leads to the removal of the microclots also removes the other symptoms. Fibrin amyloid microclots represent a novel and potentially important target for both the understanding and treatment of Long COVID and related disorders.

Pregnant Women Infected with Coronavirus Disease 2019 Pneumonia: A Case Series in Medan, Indonesia

BACKGROUND: Pregnancy state affects the immune regulation including physical barrier, innate, and adaptive immunity-related to susceptibility of infections and increasing risk for severe to critical case of COVID-19. Further, high risk of thrombosis becomes a challenge in the management of COVID19 in pregnancy due to the strong association with worse outcome. CASE REPORT: Here, we present three cases of pregnant women infected with COVID-19 pneumonia with different outcomes in maternal and fetal condition related to high-risk thrombosis. Serial inflammatory markers were needed to the early detect the disease progressivity in pregnant women with COVID-19. Further, complete assessment of fetus including reverse transcriptase-polymerase chain reaction and chest X-ray must be performed to the early diagnosis of COVID-19 in neonatal whose mother was infected by SARS-CoV-2. CONCLUSION: Pregnancy state affects the immune regulation including physical barrier, innate, and adaptive immunity-related to susceptibility of infections and increasing risk for severe to critical case of COVID-19. Further, high risk of thrombosis becomes a challenge in the management of COVID19 in pregnancy due to the strong association with worse outcome. Although fetal transmission of COVID-19 to fetus remains unclear, complete assessment of fetus including RT-PCR, and chest X-ray must be performed to the early diagnosis of COVID-19 in neonatal whose mother was infected by SARS-CoV-2.

Massive pulmonary embolism complicating mild Covid 19 pneumonia: Successful systemic thrombolysis using rt-PA in an elderly patient: A case report

INTRODUCTION

and importance: Pulmonary embolism (PE) is still a major health concern around the world, and its link with SARS Cov-2 has led to an increase in morbidity, mortality, and ICU hospitalizations.

CASE PRESENTATION

We present the case of a 92-year-old man with no prior medical history who admitted to our hospital in a state of acute respiratory failure, echocardiography revealed an acute right heart syndrome with a thrombus in the right atrium, computed tomography pulmonary angiogram revealed bilateral massive pulmonary embolism as well as Covid-19 pneumonia. He was treated with systemic thrombolysis using intravenous rt-PA (recombinant tissue plasminogen activator) with immediate clinical improvement and no hemorrhagic complications.

CLINICAL DISCUSSION

In the presence of the SARs Cov-2 infection, several reports have indicated considerable procoagulant events, including life-threatening pulmonary embolism. There are still no current guidelines for the treatment of VTE in COVID-19 patients, but they are largely consistent with non-COVID-19 recommendations. Elderly patients are considered to be at high risk of developing thromboembolic complications, and also and above all are vulnerable to bleeding complications from anticoagulant treatments.

CONCLUSION

This case highlight the importance of considering thromboembolic complications despite the severity of the associated SARS-cov-2 pneumonia and the role of prophylactic anticoagulation for Covid-19 patients hospitalized or not.